One method for controlling a brushless DC motor a method which detects the rotational angle of a rotor of the motor based on information of a position sensor such as a Hall element, adjusts the phase of a drive voltage of a drive signal that drives the motor in accordance with the detected rotational angle and outputs the resultant signal to the motor.
The position sensor is attached to the motor in a predetermined position thereof. If an attachment error of the position sensor occurs, even when the phase of the drive voltage of the drive signal is adjusted based on the information of the position sensor, the maximum efficiency cannot be attained.